Modelling of raked pile foundations in liquefiable ground

Abstract Raked piles are believed to behave better than vertical piles in a laterally flowing liquefied ground. This paper aims at numerically simulating the response of raked pile foundations in liquefying ground through nonlinear finite element analysis. For this purpose, the OpenSees computer package was used. A range of sources have been adopted in the definition of model components whose validity is assessed against case studies presented in literature. Experimental and analytical data confirmed that the backbone force density–displacement (p–y) curve simulating lateral pile response is of acceptable credibility for both vertical and raked piles. A parametric investigation on fixed-head piles subject to lateral spreading concluded that piles exhibiting positive inclination impart lower moment demands at the head while those inclined negatively perform better at liquefaction boundaries (relative to vertical piles). Further studies reveal substantial axial demand imposed upon negatively inclined members due to the transfer of gravity and ground-induced lateral forces axially down the pile. Extra care must be taken in the design of such members in soils susceptible to lateral spreading such that compressive failure (i.e. pile buckling) is avoided.

[1]  T. G. Sitharam,et al.  NONLINEAR FINITE-ELEMENT MODELING OF BATTER PILES UNDER LATERAL LOAD , 2001 .

[2]  Ricardo O. Foschi,et al.  COUPLED P-Y T-Z ANALYSIS OF SINGLE PILES IN COHESIONLESS SOIL UNDER VERTICAL AND/OR HORIZONTAL GROUND MOTION , 2005 .

[3]  Ross W. Boulanger,et al.  Static pushover analyses of pile groups in liquefied and laterally spreading ground in centrifuge tests - eScholarship , 2007 .

[4]  Michael McVay,et al.  Centrifuge modelling of laterally loaded single battered piles in sands , 1999 .

[5]  Misko Cubrinovski,et al.  PSEUDO-STATIC ANALYSIS OF PILES IN LIQUEFIABLE SOILS: PARAMETRIC EVALUATION OF LIQUEFIED LAYER PROPERTIES , 2008 .

[6]  Ross W. Boulanger,et al.  Seismic Design of Pile Foundations for Liquefaction Effects , 2007 .

[7]  Misko Cubrinovski,et al.  Case Studies of Pile Foundations Undergoing Lateral Spreading in Liquefied Deposits , 2004 .

[8]  Los Angeles,et al.  in Civil Engineering , 1996 .

[9]  R. Dobry,et al.  EFFECT OF LIQUEFACTION ON LATERAL RESPONSE OF PILES BY CENTRIFUGE MODEL TESTS , 1999 .

[10]  Christopher R. McGann,et al.  Simplified Procedure to Account for a Weaker Soil Layer in Lateral Load Analysis of Single Piles , 2012 .

[11]  K. Tokimatsu,et al.  Effects of Liquefaction-induced Ground Displacements on Pile Performance in the 1995 Hyogoken-Nambu Earthquake , 1998 .

[12]  Christopher R. McGann,et al.  Applicability of Conventional p-y Relations to the Analysis of Piles in Laterally Spreading Soil , 2011 .

[13]  Misko Cubrinovski,et al.  Simplified Method for Analysis of Piles Undergoing Lateral Spreading in Liquefied Soils , 2004 .

[14]  J. B. Berrill,et al.  Case study of lateral spreading forces on a piled foundation , 2001 .

[15]  William P. Dawkins,et al.  Theoretical Manual for Pile Foundations , 2000 .

[16]  W.D.L Finn,et al.  Piles in liquefiable soils: seismic analysis and design issues , 2002 .

[17]  G G Mayerhof,et al.  Bearing Capacity and Settlement of Pile Foundations , 1976 .

[18]  Ross W. Boulanger,et al.  Recommended Design Practice for Pile Foundations in Laterally Spreading Ground , 2011 .

[19]  Takahiro Sugano,et al.  Soil-Pile Response to Blast-Induced Lateral Spreading. I: Field Test , 2006 .

[20]  Fred H. Kulhawy,et al.  Drilled Shaft Foundations , 1991 .

[21]  S. Brandenberg,et al.  Pile Foundations in Liquefied and Laterally Spreading Ground During Earthquakes: Centrifuge Experiments & Analyses , 2003 .

[22]  J. B. Berrill,et al.  Observations Of The Earthquake Response Of Foundations In Soil Profiles Containing Saturated Sands , 2000 .